in level 9 and 10 it's a 34AA at states in our region (region 7). Technically it goes by region, but I'm not aware that any of the 8 regions currently have any different qualification system for level 9 and 10 right now.
Level 8 is a different story and that's where there's more variation. Some regions do a flat 34AA at states system in level 8, but in region 7 it goes by placement. The top 6 in each age group make up the VA team at R7 level 8 regionals. Two alternates (7th and 8th) qualify to the two "all star" teams at regionals made up of a gymnast from each state (VA, MD, DE, PA, WV, NJ).
It gets a little more confusing because the smaller states can't always fill all 8 of their spots in all age groups. So there is a system where further alternates from the larger states (VA included) usually compete on the other state teams or in All-Star slots. This is all decided after the conclusion of all the state meets.